Lava Falls Trail is a 2.8 mile lightly trafficked out and back trail located near Colorado City, Arizona that features a river and is rated as difficult. The trail is primarily used for hiking and trail running and is best used from September until May.
If you really want a good perspective of the trail, use Goggle earth instead. There is one fairly flat portion just before the final descent. The river itself is fairly anti-climatic but it's good for bragging rights to complete the hike. 3 hours down, 5 hours up(average). Whitmore Canyon Trail is a much easier way to get down to the Colorado River.
The description of this trail is misleading. There are large rapids at the bottom but I wouldn't call it a waterfall.
The trail is grueling and hard to find at times, but it was fun to go to the bottom of the Grand Canyon and back in less than a day.